Mixtures with more than one component in each class

6 Mixtures with more than one component in each class 

Consider the information to be obtained from SDS/BEC or NaTPB titrations at high and low pH. 

Consider what other functional groups are present which might offer a route to any of the components, e.g. hydroxyl groups (hydroxyl value), free acidic or basic groups that can be titrated, ester groups (saponification value) or polyalkenoxy chains (colorimetry, NaTPB titration of barium complexes), etc. 

Consider what labile groups are present which would yield extractable hydrolysis products, e.g. amide groups yielding fatty acid, or whose decomposition would prevent their determination by some other procedure, e.g. SDS/BEC titration after acid hydrolysis of sulphates, esters or amides. 

Not all mixtures are amenable to this approach, or are perhaps amenable in principle but would require an impracticably complicated scheme of analysis. But with the right strategy, and preferably with some crosschecking by using alternative routes or a mass balance, a high proportion of multicomponent mixtures can be analysed by the techniques described in the preceding chapters. 

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